This battery has a different plus pole than most other high capacity LiIon batteries, it uses the small diameter button.
The cell used can be discharged down to 2.5 volt, in my test I only discharges to 2.8 volt, i.e. I do not measure the full capacity. But then, not all lights will be able to use the full capacity.

Shipping was in a plastic box within a sealed plastic bag.

Conclusion

This battery uses a good cell, this secures many things:

The batteries does match in capacity, i.e. they can be used in series.

The battery is very safe.

The battery has the specified capacity.

The use of a small button top makes this battery interesting for some application, but the price for this top is that the battery is one of the longer 3100 mAh batteries.
All in all a very good battery.

Note: ENERDan has improved the welding process, this might reduce the internal resistance.